1. Field of the Invention
The present invention relates to the field of a digital signal processing system, and more particularly, to a digital image processing system, such as video cameras, digital cameras, cathode ray tubes (CRT), etc.
2. Description of the Prior Art
In general, a picture signal is separated into a brightness signal and a color signal while it is being transmitted or stored. That is, a color image signal applied to a video camera organizes the brightness signal from the three primary colors of light (red, blue and green).
Conventionally, the devices for calculating a brightness signal have been implemented by using a multiplication circuit, and the general equation (1) for calculating it is as follows: EQU Brightness (Y)=0.587G+0.299R+0.114B (1)
wherein, the parameter G is the value for a green signal of a picture signal, R for a red signal and B for a blue signal. According to equation (1), the calculation of the brightness signal requires the calculation of three or more significant figures to be accurate.
Therefore, the devices for calculating the brightness signal need more bits for calculating than the input bits. Also, it is very difficult to apply them to a system requiring high resolution, such as video cameras, cathode ray tubes, etc., because too much time is required in carrying out the multiplications or divisions.